This invention relates to a dried sludge melting furnace apparatus in which dried sludge and combustion air are supplied to a primary combustion chamber, and the dried sludge is converted into slag in the primary combustion chamber and a secondary combustion chamber and then separated from the combustion gas in a slag separation chamber.
Conventionally, a dried sludge melting furnace apparatus of this kind and having the following structure is proposed. In such an apparatus, at least one temperature detector disposed at an appropriate position of a primary combustion chamber (PCC) detects the temperature of the PCC (referred to as "detected PCC temperature"), a temperature detector disposed at a lower portion of a slag separation chamber detects the temperature of slag (referred to as "detected slag temperature"), and a nitrogen oxide (NOX) concentration detector and oxygen concentration detector disposed at an upper portion of the slag separation chamber detect the NOX concentration (referred to as "combustion gas NOX concentration") and oxygen concentration (referred to as "combustion gas oxygen concentration") of combustion gas, respectively. While monitoring these detected values, the operator manually operates based on experience control valves, a control valve disposed in a dried sludge supply pipe which opens in the top of the PCC, control valves disposed in combustion air supply pipes which respectively open in the upper and lower portions of the PCC, a control valve disposed in a fuel supply pipe which is communicated with a burner disposed at the top of the PCC, a control valve disposed in a combustion air supply pipe which opens in a secondary combustion chamber (SCC), and a control valve disposed in a fuel supply pipe which is communicated with a burner disposed in the SCC, thereby adjusting the amount of dried sludge (referred to as "dried sludge supply amount") and amount of combustion air (referred to as "PCC combustion air supply amount") supplied to the PCC, the amount of fuel (referred to as "PCC burner fuel amount") supplied to the burner disposed in the PCC, the amount of combustion air (referred to as "SCC combustion air supply amount") supplied to the SCC, the amount of fuel (referred to as "SCC burner fuel amount") supplied to the burner disposed in the SCC.
In such a conventional dried sludge melting furnace apparatus, while monitoring the detected PCC temperature, the detected slag temperature, the detected combustion gas NOX concentration and the detected combustion gas oxygen concentration, the operator must adjust, in accordance with the change of these values and based on experience, the dried sludge supply amount, the PCC combustion air supply amount, the PCC burner fuel amount, the SCC combustion air supply amount and the SCC burner fuel amount. Therefore, the conventional dried sludge melting furnace apparatus has the following disadvantages: (i) the operator must always be stationed in a control room; (ii) the operation accuracy and efficiency change depending on the skill or experience of the operator; (iii) it is impossible to lengthen the lifetime or service life of the furnace casing; and (iv) the dried sludge supply amount, the PCC combustion air supply amount, the SCC combustion air supply amount, the PCC burner fuel amount and the SCC burner fuel amount are susceptible to frequent changes.